1. Field of the Invention
The present invention relates to devices for handling pneumatic flow, and particularly to a heat exchanger flow balancing system incorporating means for controlling the pneumatic flow through each of the multiple tubes of a heat exchanger in order to create substantially equal flow through each tube.
2. Description of the Related Art
Heat exchangers, also known as radiators in many applications, are used in a wide variety of applications including stationary and vehicle heating and air conditioning systems, engine supercharging and turbocharging intercooler systems, power generation, and other mechanical and pneumatic systems of various types. The heat exchangers manufactured for these systems are generally relatively simply constructed, with their heat exchanging tubes all being cut from the same stock material to have the same diameters and wall thicknesses. Generally, a single header or entry plenum is provided, with this plenum having a single relatively large diameter inlet with a relatively large number of equal diameter heat exchanger tubes extending to an outlet plenum with its single large diameter outlet or exhaust tube. The inlet and outlet tubes may connect to their respective plenums at either end of the plenum or at some point at or near the center of the plenum, or perhaps at some other location on the plenum depending upon manufacturing considerations, physical constraints for the intended installation, and perhaps other factors.
The problem with such equal tube diameter heat exchangers is that the fluid flow varies to each of the individual tubes, depending upon the distance of the tube inlet from the larger single intake tube of the plenum (and perhaps other factors as well, such as any changes in direction of airflow from the inlet tube to the individual heat exchanger tubes). Much the same problem can occur at the outlet plenum as well. This can result in significant variation in the fluid flow through the heat exchanger tubes located at some distance from the large intake tube, in comparison to those heat exchanger tubes having their inlets adjacent to the inflow from the single large intake tube. The result is that the heat exchanger is far less efficient than it might otherwise be, if the fluid flow were at least close to equal through each of the individual heat exchanger tubes.
Innumerable heat exchanger and radiator configurations have been developed in the past, as noted further above. An example of such is found in German Patent Publication No. 2,209,684 published on Sep. 13, 1973 to Karl Heinkel Apparatebau KG. This reference describes a heat exchanger having a two-way flow path contained within a single plenum, with the two flow directions separated by an internal wall. A series of tubes extend from the inlet side of the plenum, with these tubes contained concentrically within larger diameter tubes. Fluid flowing into the inlet side and through the smaller diameter tubes leaves the smaller tubes at their open distal ends, flowing into the surrounding larger diameter tubes and returning to the outlet side of the plenum.
Thus, a heat exchanger flow balancing system addressing the aforementioned problems is desired.